Weft detector for pick and pick loom



Nov. 15, 1955 P. A. NlMs 2,723,685

WEFT DETECTOR FOR PICK AND PICK LOOM Filed Nov. l0, 1954 2 Sheets-Sheet l FIG. l

ATTORNEY Nov. 15, 1955 P. A. NlMs WEFT DETECTOR FOR PICK AND PICK LOOM Filed NOV. lO, 1954 2 Sheets-Sheet 2 FIG.4

` INVENTOR PHILIP A. NIMS ww. mf@

ATTORNEY United States Patent O WEFT DETECTOR FOR PICK AND PICK LOOM Philip A. Nims, Worcester, Mass., assigner to Crompton & Knowles Loom Works, Worcester, Mass., a corporation of Massachusetts Application November 10, 1954, Serial No. 467,955

16 Claims. (Cl. 139-233) This invention relates to improvements in control means for the weft detector of an automatic pick and pick loom and it is the general object of the invention to provide a control which can lock the detector out of action during part of the loom operation and then un lock the weft detector for operation during selected beats of the loom whether the detector be in a low or a high position in register with one of the shifting shuttle boxes at the magazine end of the loom.

A recently developed method for the automatic weaving of 2-color pick and pick fabric employs the principle of operating the loom for a series of picks nonautomatically to be followed by another series in which weft replenishment can occur. When operating in this manner it is necessary to utilize some means which will prevent the detector from initiating a replenishing operation throughout the nonautomatic series and also during certain picks or beats of the loom in the automatic series. A control for effecting this result has already been proposed and utilizes an electric circuit having two normally open switches one of which is closed by a chain moving in time with the shuttle box control chain and the other closed by the detector when it indicates weft exhaustion. By this means the beat of the loom on which the detector can indicate weft exhaustion is determined by the chain but if on these picks of the loom the detector should inadvertently close its switch when replenishment is not necessary, there will be an undesirable weft replenishing operation which may result in ejecting a full or partially full bobbin.

'I'he pick and pick operation of the loom requires that shifting shuttle boxes be used at the magazine end and the weft detecting system to which the invention more particularly relates employs a detector which rises and falls with the corresponding motions of the shuttle boxes so that at times the detector is in low position and at other times in a high position. It is an important object of the present invention to provide a weft detector of the rising and falling type and of the kind which gives indication of weft exhaustion mechanically and wherein the detector will be locked in nonindicating position but can be unlocked for a detecting operation irrespective of its vertical position.

It is another object of the invention to provide an electromagnetic control for the locking means for the detector which enables the lock means to hold the detector in nonindicating position and then on selected beats moves the locking means to releasing position so the detector can move to detecting position.

The detector to be described in more detail hereinafter is moved forwardly to a locking position mechanically whenever engaging an ample weft supply during a detecting beat of the loom. The detecting operation occurs It is a `further object of the' invention to energize the 2,723,685 Patented Nov. 15, 1955 ice magnetic vcontrol momentarily to unlock the feeler on the selected beats of the loom before the layreaches front center and then deenergize the control so the lock can return to locking position to relock the feeler, if ample weft is present, when the lay is at front center.

The amount of weft on a bobbin sufcient to prevent the detector from indicating weft exhaustion may vary from a full bobbin down to a bobbin which is almost empty so that the detector will be given varying amounts of forward motion by the weft depending upon the amount of the latter on the bobbin being detected. It is a further object of the invention to provide a plurality of locks one of which will act to lock the feeler when it is given a minimum forward motion by the weft in one shuttle and the other of which can lock the detector when it is given its maximum forward motion by the weft in another shuttle.

In order that the previously mentioned locking may operate eciently it is a further object of the invention to make the locks preferably in the form of springs disposed obliquely with respect to the back and forth sliding motion of the detector in such a way that accidental unlocking would require forward motion of the detector against the action of the spring which normally tends to hold it in rear position. This disposition of the locks, while effective to prevent accidental unlocking, would also render intentional unlocking difficult unless provision were made to move the locks in a direction in which they would not be required to operate against the said spring. This result is accomplished by mounting the electromagnetic device, such as a solenoid, and a lever which it operates in a plane such that the Obliquity of the locks will not change relative to the detector during the unlocking operation. In this way safety against ac cidental unlocking is retained but the intentional unlocking can be effected easily without subjecting the solenoid and parts operated by it to undue strain.

It is a further object of the invention to provide an improved weft detector unit including a support having a detector slidable thereon and an electromagnetic device thereon to control a lock lever pivoted on the support. The lock lever normally holds the detector locked out of action but permits the detector to move to detecting position when rocked by energization of the electromagnetic device.

In order that the invention may be clearly understood reference is made to the accompanying drawings which illustrate by way of example one embodiment of the invention and in which:

Fig. l is a plan view partly in section of the weft detector and associated and control parts therefor,

Fig. 2 is a vertical section on line 2 2, Fig. l,

Fig. 3 is an enlarged vertical section on line 3 3, Fig. 2,

Fig. 4 is a diagrammatic view similar to parts shown in Fig. l, but indicating the detector nger in engagement with a full weft supply so that the detector has been moved to its maximum forward locked position,

Fig. 5 is a view similar to Figi 4 but indicating the detector unlocked and in engagement with a depleted weft bobbin,

Fig. 6 is a diagrammatic side elevation showing the control for the weft detector in unlocked position,

Fig. 7 is a diagrammatic view of a form of warp harness and shuttle box control mechanism together with the switch and chain therefor for control of the lock operating solenoid, and

Fig. 8 is a diagrammatic view of an electric circuit which can be used with the invention.

The loom to which the invention may be applied is usually equipped with some form of harness and shuttle box operating mechanism, suchfor instance as the wellly known Knowles head K shown in Fig. 7. This head is mounted on an arch 1 of the loom and includes top and bottom continuously turning mutilated cylinder gears 2 and 3 respectively for operation of vibrator gears 4. Each vibrator gear is mounted on a vibrator lever 5 the vertical position of which is determined by a pattern chain not shown herein but driven by a pattern chain shaft 6 which will Ordinarily run continuously during loom operation. Certain of the vibrator gears are attached to connectors 7 for operating the shifting shuttle boxes which are at each end of the loom. In Fig. 7 only one vibrator gear 4, vibrator lever ,5 and connector 7 is shown, but it is to be understood that several of these vibrator lever units are arranged side by side in the usual manner. The head includes box operating levers 8 and 9 which by flexible connections '10 and 11 control the vertical position of the shuttle boxes with respect to the lay 12 shown in Fig. l.

The shaft 6 is operatively related to and drives a control chain C made up of a plurality of bars 13 and moves in time relation with the usual harness and box chains so that one bar will be moved to a position over the shaft 6 for each pick or beat of the loom, that is, there will be as many bars in the chain C as there are beats of the loom in the sequence of picks in the operation of the loom.

Referring more particularly to Figs. 1 and 2, the gang G of shuttle boxes at the right-hand or weft replenishing end of the loom has upper and lower shuttle box cells 15 and 16 respectively mounted on a box lifter rod 17 which extends down to the usual box lifting mechanism (not shown) operated from one or the other of the levers 8 and 9. Each shuttle box is provided with the usual binder 18 and the shuttles S1 and S2, each of which can enter box 15, have slots 20 to register with slot 21 in the upper binder when properly boxed.

The loom is provided with a stationary support on which is mounted a small control shaft 26 having secured thereto an upright arm 27 to which is pivoted a controller pin 28 extending rearwardly, to the right as viewed in Fig. 2. This pin is for cooperation with an actuator lever 30 pivoted intermediate its ends to the upper end of a rod head 31 which reciprocates vertically in part of the stand 25. The left end of lever 30, see Fig. l, is pivoted to an upwardly extending rod 32 which is connected to weft replenishing mechanism of the usual stationary multi-color type not shown herein but well understood. The rod head 31 moves down when the lay is on or near front center position and if the rod 28 is under lever 30 the rod 32 will be depressed to initiate a replenishing operation. If, on the other hand, the rod 28 is in a forward position the right-hand end of lever 30 as viewed in Fig. 1 will have an idle downward motion and the rod 32 will remain at rest without initiating a replenishing operation. The down motion of the rod head 31 can occur as usual every other pick of the loom, or every pick of the loom as contemplated for instance in co-pending Kimmel application, Serial No. 425,138. So far as certain features of the present invention are concerned it is immaterial whether rod 31 has a rising and falling motion every pick or only every other pick of the loom.

The weft detector designated generally at D is of the mechanically indicating side slipping type and has a horizontal slidable carrier 35, to the rear of which is pivotally mounted a side slipping weft detector nger 36 which is normally held in the position shown in Fig. 1 against a stop screw 37 but can slip to the right as shown in dotted line, Fig. 5 when engaging a depleted supply of weft. The carrier slides back and forth in a fixed path on a support 40 on which is mounted spring 41 the rear end of which is operatively related to the carrier 35 and the forward end of which abuts the support. The elect of the spring is to tend to move the carrier and its detector linger to rearward position.

The support 40 is mounted on a slide 42 which is guided for vertical motion in guide 43. A rod 44 is pivoted to the lower end of the slide 42 and extends down to have connection with the mechanism which raises and lowers the gang G so 'that rods 17 and 44 move upwardly and downwardly in unison. The detector D during its rising and falling movements is kept in register with the upper shuttle box 15.

The short shaft 26 has secured thereto a second arm 45 which bears against a vertical positioner 46 pivoted at 47 to a stationary part of the loom. The upper end of the positioner 46 lies in front of and in engagement with the forward end of the slide carrier 35 and is held in that position by a spring 50 disposed around the shaft 26. This spring acts in the usual manner and in addition to holding the positioner against the carrier it also tends to move the controller pin 28 rearwardly to a position under lever 30. The spring 5) will yield, however, to permit rocking of shaft 26 and forward motion of controller pin 28 when the positioner is moved forwardly by carrier 35.

The transter arm (not shown) which descends on replenishment operations of the loom to press a fresh bobbin into the shuttle in the upper cell 15 is provided with a roll 51 which moves forwardly during replenishment to engage a lug 52 on the carrier 35 to move the latter forwardly and thus advance the feeler finger 36 out of the path of the incoming bobbin. The rearward position ofthe carrier 36 may be determined by a screw 53 which engages a stop, such as vertical screw 54 on the support 49. A revoker finger 55 may be secured to the carrier 35 to engage a misplaced shuttle and move the detector forwardly to prevent detection by the linger 36 in the event that the shuttle is misplaced, but this revoker 55 is not necessary for all features of the invention, although the forward motion of the carrier 36 which it produces will restore the detector to locked position if uniocking has previously occurred, as will be described hereinafter.

tn the operation of the matter thus far described the weft detector rises and falls in register with the top shuttle box cell 15 and as the lay moves forwardly with a shuttle in boX 15 its bobbin B will exert a forward force on the ringer 36. lf sutlicient weft for continued weaving is present on the bobbin, as indicated at W in Fig. l, the finger will be prevented from slipping to the right and as the lay advances toward its front center position the finger 36 will cause the carrier 35 to slide forwardly against the action of spring 41 and rock the arm in 4a counter clockwise direction, Fig. 2, to pull the controller pin 28 from under the lever 3i?. Under these conditions the latter lever will have an idle down motion without setting the loom for a weft replenishing operation. it', on the other hand, the supply of weft should be depleted the nger 36 will then slip laterally without substantial forward motion of the carrier 35, see dotted lines Fig. 5, and the controller pin 26 will remain under the actuator lever 3) and a weft replenishing operation will be initiated.

The matter thus far described and the operation thereof, except as noted hereinafter, is well-known and may be made as set forth for instance in prior Patent No. 2,391,602 to which reference may be had for further detailed description of the structure and operation.

As already stated, it is to be understood that the invention relates more particularly to those types of looms developed recently for the automatic replenishment of two shuttles running pick and pick. in such looms shuttle S1 for instance can enter the box cell 1:5 when the gang G is down and will then immediately be lifted to inactive position to permit activity of shuttle S2 on the next pick of the loom. The gang G will then descend so that shuttle S1 can again be active on the third beat and this mode of operation will continue throughout the nonautomatic series of beats which are represented for instance by the low rolls at the right-hand and lower left part of chain C shown in Fig. 7. After the nonautomatic series of beats has been completed there follows what is generally a shorter series of beats in an automatic period of weaving in which replenishment can occur if necessary. During this automatic period the loom may have one or more blank picks occasioned bythe fact that the gang G will remain in up position for two successive beats of the loom. During the nonautomatic series of picks the weft detector as shown herein would be held in the nondetecting position so that even though the shuttle in top box should become depleted the detector cannot initiate a replenishing operation. To take care of a depletion which occurs during the nonautomatic series of beats the bobbins may be provided with large bunches of reserve weft as shown for instance in copending application, Serial No. 389,548. When the automatic series is reached, however, the detector must. be permitted to perform a detecting operation on those beats of the loom in which a shuttle is in the top cell 15 and gang G is rising. This result is accomplished by the means which will now be described.

The support 40 has an arm 65 which is secured thereto by stop screw 54. A solenoid S is secured to arm 65 at 66 and has a core 67 which projects normally rearwardly beyond the solenoid and has its forward end pivoted at 68 to the upper arm 69 of a lever designated generally at L and rocking about a pivot stud 70 carried by the arm 65. v

The details of this construction are shown in Fig. 3 where it will be seen that a nut 71 screw-threaded on the left hand part of the stud 70 secures the latter to the arm 65, the stud having a flange 72 which is drawn against the arm by the nut Secured as shown to the right-hand end of stud 70 for angular adjustment thereon is a barrel 73 containing a torsion spring 74 which is effective to turn the lever L in a clockwise direction as viewed in Fig. 2. The force of the spring is adjustable by turning the barrel on the stud and normally holds lever L rearwardly in the position shown in Fig. 2.

The lever L has a generally horizontally extending forward arm 75 to which are secured two spring lock elements 76 and 77 of different lengths. These locks may be made of spring steel or similar material and are adapted for engagement with a cooperating lock member 78 shown herein as a washer around the stop screw 53. The washer is held firmly in position with respect to the carrier 35 by a lock nut 79 and the washer extends to the right beyond the carrier 35 as shown for instance in Figs. l, 4 and 5.

The spring locks 76 and 77 are disposed obliquely with respect to the line of back and forth sliding of the carrier 35 and their forward ends are substantially aligned in a direction parallel to the direction of sliding so that either of the spring locks 76 and i7 can engage the stop washer 78.

Fig. 8 shows diagrammatically a circuit which can be used with the invention, this circuit including normally an open switch 85 which is controlled by a lever 86 pivoted on the head K and controlled as to vertical position by the rolls on the chain C. The circuit also includes the solenoid S, a source of electric power l?, and connecting wires which will effect energization of the solenoid whenever the switch 85 is closed. When the circuit is closed the core 67 will be moved forwardly, or to the left as viewed in Fig. 2, to rock the lever L in a counter clockwise direction, Fig. 2, to the unlocked position shown in Fig. 6.

In operation, the solenoid is ordinarily deenergized due to the fact that switch 85 will be open because of the presence of low rolls 90 on the chain C under lever 86 and the two spring locks are therefore in locking position so that one or the other of them can have engagement With the stop washer 78. The lock element which engages member 78 will hold the carrier 35 forwardly in nondetecting position, thereby preventing the detector from indicating weft exhaustion. When a beat of the loom arrives on which it is desired to have the detector operate, a large roll 91 on chain C will arrive under the lever 86 and lift the latter to close switch 85, whereupon the solenoid will rock lever L from the position shown in Fig. 2 to the position shown in Fig. 6, thereby moving the spring locks downwardly away from the stop washer 78 to release the detector and permitting spring 41 to move the detector rearwardly for a detecting position. This release occurs some time prior to arrival of the lay at front center, and if the detector finger 36 would engage a full supply of weft the carrier 35 will be moved forwardly a considerable distance and it should be relocked in that position by spring lock 77.

In order to effect this relooking on a detecting beat the solenoid must be deenergized to permit spring 74 to return the spring locks to their locking position not substantially later than front center. This requires that the circuit shown in Fig. 8 be opened before the actual detecting operation is completed. To accomplish this result the run 92 on the lever 86 will be short so that lever 86 will be raised for only a brief interval of time, just long enough to elfect unlocking of the detector. It is to be understood that the unlocking will occur preferably during the early part of the forward motion of the lay so that the solenoid can be energized to unlock the detector and then be deenergized to permit relocking of the detector when the lay is at front center.

If after the detector has been unlocked it engages a depleted supply of weft as suggested in Fig. 5 the controller pin 28 will remain under the actuator lever 30 and av replenishing operation will be initiated. Under these conditions the carrier 3S will remain in rear position subsequent to the front position of the lay on which indication of weft exhaustion is given, but on the next forward motion of the lay replenishment will occur and the roll 51 by its engagement with lug 52 will move the carrier 35 forwardly so that it can again be locked in forward position, the chain C on this beat of the loom having a low roll under lever 86 and the spring locks having previously been returned to their locking position.

It is to be understood that if the detector finger 36 engages a small suply of weft which is almost depleted the linger will move forwardly so that at least the shorter spring lock 76 will be able to engage the lock washer 78. If at a` later time a full bobbin engages the finger the carrier will then be given an additional forward motion and will be held by the spring lock 77, as in Fig. 4.

In the foregoing description it has been assumed that the detector would need to be unlocked when moving up from a low position during rising motion of the gang G, but another condition of operation can ensue in which the detector must rst be raised to its high position while locked and then be unlocked when in high position. Thus, if the gang G is down and both cells are empty a shuttle as S1 could enter the top cell 15 and then the gang would rise and during the next two beats of the loom anothershuttle would be active, coming irst into cell 16 on one beat and then being picked out on the next beat. Under these conditions if indication were given during up motion of the boxes and a replenishment operation were called it would take place when the second shuttle was still in the lower box, blocking the path of the outgoing bobbin. Under this mode of operation, therefore, it would be necessary to let the feeler reach its high position while locked and unable to indicate and then release it for detecting operation for the rst beat during which it is in its full up position. From this it will be seen that the detector should be releasable to perform a detecting operation either at the time when it is at or near its low position or on the next beat when in its high position, as the case may be. The chain C can effect release of the detector under either of these two conditions and the solenoid, since it rises and falls with the support 40, can effect release of the detector whether the latter be in low or high position.

From the foregoing it will be seen that the invention sets forth a weft detector which rises and falls with shifting shuttle boxes and is normally locked in nondetecting position butcan be released to move to detecting position irrespective of its elevation in the loom, that is, whether 7 in low or high position -or moving from one of theseiposi- -tions to the other position. The detector when unlocked lhas a tendency to move toward detecting Vposition where it performs its detecting operation mechanically. Both the lock means and the solenoid which controls it rise and fall with the detector due to the fact that they are mounted on support 40 which shifts vertically to cause the detector to register with the upper shuttle box .15. The electrical parts set forth may be considered vgenerally as a control mechanism for the lock means and the tor- Sion spring for the lever L may be considered additional means tending normally to move the lock lever to locking position. The lock means includes spring elements 76 and 77 of different lengths to lock the detector in two different positions and these elements are oblique or inclined with respect to the path of sliding of the carrier 35 in a direction away from the path and toward the given direction in which the spring 41 tends to move the carrier. The lock elements are of diierent lengths but their free forward ends are equidistant from the path of movement of the carrier so that each is efective to engage the cooperating locking member 78. The run on the lever 86 is very short so that the solenoid can be energized briefly while the shuttle `boxes are in rearward position and then be deenergized to permit return of the locks to locking position not substantially later than arrival of the shuttle boxes at their front center position to permit rte-locking of the detector as the .latter engages an ample supply of weft in its detecting operation. More specifically the solenoid can be considered to be release means to move the lock means to its unlocking position.

While the detector control has been described in connection with a Z-shuttle pick and pick loom certain aspects of the invention are not necessarily limited to .use in such a loom. Also, the parts mounted on the support, such as a detector, the locking lever, the member 78 and the solenoid constitute an assembled and self-contained detecting unit.

Having now particularly described and ascertained the nature of the invention and in what manner the same is to be performed, what is claimed is:

l. In a loom operating with vertically shifting shuttle boxes, a weft detector which has a tendency to move to detecting position when free to -do so and rises and falls in register with one of said boxes as the latter shift to be in either high or low position, depending upon the position of the boxes, lock means to hold the detector in nondetecting position when the detector is in leither high or low position, and control mechanism for the lock means effective whether the detector be in high or low position and on any selected beat of the loom to move the lock means to unlocking position, whereupon the detector due to said tendency moves to detecting position.

2. The loom set forth in claim l wherein the shuttle boxes move toward a front center position each detecting beat of the loom and the detector if free to do so has a detecting operation when the boxes areat or near their front center position, and the control mechanism causes the lock means to move to unlocking position to release the detector and then return to locking position relative to the detector prior to arrival of the boxes at its front center position to enable the lock means to relock the detector in nondetecting position if the detector is moved by an ample supply of weft in the shuttle being detected.

3. The structure set forth in claim l wherein the lock means rises and falls with the detector.

4. The structure set forth in claim l wherein the lock means includes at least two lock elements of dilerent lengths one of which is effective to lock the detector if the latter is given a relatively `small motion by a nearly depleted supply of weft and the other of which is effective to lock the detector if the latter is given a larger motion by a larger supply of weft.

5. The structure set forth in claim l wherein the lock means includes a spring lock element to engage and be deflected by a lock cooperating member on the detector when the latter is returned from a detecting position to locked nondetecting position.

6. The structure set forth in claim l wherein the detector is mounted to slide in a back and forth path relative to the shuttle boxes and the lock means includes a spring element inclined rearwardly and away from said path.

7. The structure set forth in claim l wherein the control mechanism includes a solenoid in an electric circuit which is closed to energize the solenoid on selected beats of the loom and the solenoid when energized moves the lock means to unlocking position relative to the detector.

8. The structure set forth in claim 7 where in the solenoid and lock means rise and fall with the detector.

9. The structure set forth in claim 7 wherein the shuttle boxes move toward and away from the front center position thereof each beat of the loom and the detector when free to do so has a weft detecting operation when the boxes are at or near their front center position, means are provided to close said circuit on any selected beat of the loom and thereafter open said circuit prior to the following front center position of the boxes, and additional means returns the lock means to locking position upon opening of the circuit to the end that if the detector engages an ample supply of weft it can be relocked in nondetecting position.

l0. The structure set forth in claim 7 wherein the lock means has a tendency to move to locking position relative to the detector and the shuttle boxes move toward and away from a front center position each beat of the loom and the detector if free to do so detects when the boxes are on front center, and means are provided to etect closure of the circuit and then opening of the circuit before the boxes reach front center on said selected beats of the loom to the end that the lock means is moved electromagnetically to nonlocking position and then due to said tendency returns to locking position.

l1. In a loom operating with vertically shifting shuttle boxes, a weft detector which has a tendency to move to detecting position when free to do so and rises and falls in register with one of said boxes as the latter shift to be in either high or low position, depending upon the position of the boxes, lock means to hold the detector in nondetecting position when the detector is in either high or low position, release means to move the lock means to unlocking position with respect to the detector, a chain which moves during loom operation and has bars which move one at a time to indicating position, one bar for each beat of the loom, and means controlled by certain bars on the chain to cause said release means to release the lock means on beats of the loom corresponding to said certain bars whether the detector be in high or low position, the detector due to said tendency moving to detecting position whenever the release means moves the lock means to unlocking position.

l2. In a weft detector unit for a loom, a support, a weft detector carrier slidable back and forth in a fixed path on said support, a spring supported on the support tending to move the detector in a given direction along said path, a lock lever mounted on the support for angular movement relative thereto, a cooperating lock member on the carrier for engagement with the lock lever to prevent said spring from moving the detector in said direction, a solenoid mounted on the support, and a core for the solenoid operatively connected to the lock lever and effective to move the latter from locking to unlocking position relative to said member when the solenoid is energized to enable said spring to move the detector in said direction.

13. In a weft detector unit for a loom, a support, a weft detector carrier slidable back and forth in a xed path on said support, a spring supported on the support tending to move the detector in a given direction relative to the support, a lock lever mounted on the support for angular movement relative thereto, a cooperating lock member on the carrier for engagement with the lock lever to prevent said spring from moving the detector in said direction, and normally deenergized electromagnetic means operatively connected to said lock lever eiective when energized to move the lock lever away from said member to enable the spring to move the detector in said direction.

14. The unit set forth in claim 13 wherein the lock lever pivots on a stud fixed with respect to the support and a spring supported by the support returns the lever to 1ocking position when the electromagnetic device is deenergized.

15. The unit set forth in claim 13 wherein the lock lever is provided with a spring element which normally engages said member and is inclined to said path in a direction away from the latter and in said given direction.

16. The unit set forth in claim 13 wherein the lock lever is provided with two spring elements each capable of engaging said member to hold the detector in nondetecting position and wherein both elements are inclined to said path in a direction away from said path and in said given direction and said elements have free ends 10 normally equidistant from said path.

No references cited. 

